Length–Mass and Length–Weight Relationships of Japanese Freshwater Fishes

Abstract

Relationships between weights (W, dry weight [DW] and wet weight [WW] and lengths L, standard length [SL], head length [HL], and caudal peduncle depth [CD]) and these between DW and WW were examined in 61 freshwater fishes using formula W = aL^b and DW = aWW^b, respectively. The parameters of the SL–DW, SL–WW, HL–DW, HL–WW, CD–DW, CD–WW, and WW–DW relationships were determined for 60, 61, 57, 58, 50, 50, and 61 taxa, respectively, with the criterion where the estimated R-square was greater than 0.8. For the genus or higher taxonomic level, parameters of the SL–DW and SL–WW relationships were determined for 20 taxonomic groups with the same criterion to each species. For the three eel-like species, the SL–DW and SL–WW relationships were largely consistent with the pooled taxonomic data. In contrast, noneel-like species exhibited variations in these relationships across species. Systematic variations in the SL–DW and SL–WW relationships were observed at the order and family levels, except in Salmonidae, Cobitidae, and Cottidae. However, at the genus level, these relationships were generally consistent among species. These intragroup variations should be considered when applying these equations to ecological and taxonomic studies.